1. Field of the Invention
The invention relates to the control of a hybrid vehicle that is equipped with an internal combustion engine and a rotating electrical machine as motive energy sources.
2. Description of Related Art
There is known a hybrid vehicle that is equipped with an engine and a rotating electrical machine as motive energy sources. In such a hybrid vehicle, a deceleration force may be generated by stopping the supply of fuel to an engine (fuel cut) in decelerating the vehicle. However, when this fuel cut is performed with a three-way catalyst, which is used to purify exhaust gas, at high temperatures, the atmosphere around the catalyst may become excessively rich in oxygen (lean) to promote a deterioration in the catalyst. Thus, it is desirable to reduce the frequency of the performance of fuel cut by decelerating the vehicle through regenerative braking.
For example, according to what is disclosed in Japanese Patent Application Publication No. 2009-051466 (JP-A-2009-051466), in a vehicle that is controlled such that a remaining capacity of a storage device (which will be referred to also as an SOC in the following description) falls within a control range defined by a control upper limit and a control lower limit, the control upper limit of the SOC is raised to absorb a power generated through regenerative braking when the SOC is high and a deterioration in a catalyst is apprehended.
However, when the SOC of the storage device is increased by raising the control upper limit of the SOC as described above, the life of the storage device may be shortened through overcharge. A control apparatus disclosed in the aforementioned publication does not take this problem into account and hence cannot offer a solution.